unit DIrr.Material;

{$I DIrr.inc}

interface

uses
  DIrr.Base, DIrr.Types, DIrr.Structs, DIrr.RenderServices;

type
  //! Interface for material rendering.
  (** Can be used to extend the engine with new materials. Refer to
  IVideoDriver::addMaterialRenderer() for more informations on how to extend the
  engine with new materials. *)

  TMaterialRenderer = class(TNamedObject)
  public
    //! Called by the IVideoDriver implementation the let the renderer set its needed render states.
    (** This is called during the IVideoDriver::setMaterial() call.
    When overriding this, you can set some renderstates or for example a
    vertex or pixel shader if you like.
    \param material: The new material parameters to be set. The renderer
    may change the material flags in this material. For example if this
    material does not accept the zbuffer = true, it can set it to false.
    This is useful, because in the next lastMaterial will be just the
    material in this call.
    \param lastMaterial: The material parameters which have been set before
    this material.
    \param resetAllRenderstates: True if all renderstates should really be
    reset. This is usually true if the last rendering mode was not a usual
    3d rendering mode, but for example a 2d rendering mode.
    You should reset really all renderstates if this is true, no matter if
    the lastMaterial had some similar settings. This is used because in
    most cases, some common renderstates are not changed if they are
    already there, for example bilinear filtering, wireframe,
    gouraudshading, lighting, zbuffer, zwriteenable, backfaceculling and
    fogenable.
    \param services: Interface providing some methods for changing
    advanced, internal states of a IVideoDriver. *)
    procedure OnSetMaterial(const Material, LastMaterial: SMaterial;
      ResetAllRenderstates: Boolean; Services: TRendererServices); virtual; stdcall;

    //! Called every time before a new bunch of geometry is being drawn using this material with for example drawIndexedTriangleList() call.
    (** OnSetMaterial should normally only be called if the renderer decides
    that the renderstates should be changed, it won't be called if for
    example two drawIndexedTriangleList() will be called with the same
    material set. This method will be called every time. This is useful for
    example for materials with shaders, which don't only set new
    renderstates but also shader constants.
    \param service: Pointer to interface providing methos for setting
    constants and other things.
    \param vtxtype: Vertex type with which the next rendering will be done.
    This can be used by the material renderer to set some specific
    optimized shaders or if this is an incompatible vertex type for this
    renderer, to refuse rendering for example.
    \return Returns true if everything is ok, and false if nothing should
    be rendered. The material renderer can choose to return false for
    example if he doesn't support the specified vertex type. This is
    actually done in D3D8 and D3D9 when using a normal mapped material with
    a vertex type other than EVT_TANGENTS. *)
    function OnRender(Service: TRendererServices; vtxtype: E_VERTEX_TYPE): Boolean; virtual; stdcall;

    //! Called by the IVideoDriver to unset this material.
    (** Called during the IVideoDriver::setMaterial() call before the new
    material will get the OnSetMaterial() call. *)
    procedure OnUnsetMaterial; virtual; stdcall;

    //! Returns if the material is transparent.
    (** The scene managment needs to know this
    for being able to sort the materials by opaque and transparent. *)
    function IsTransparent: Boolean; virtual; stdcall;

    //! Returns the render capability of the material.
    (** Because some more complex materials
    are implemented in multiple ways and need special hardware capabilities, it is possible
    to query how the current material renderer is performing on the current hardware with this
    function.
    \return Returns 0 if everything is running fine. Any other value is material renderer
    specific and means for example that the renderer switched back to a fall back material because
    it cannot use the latest shaders. More specific examples:
    Fixed function pipeline materials should return 0 in most cases, parallax mapped
    material will only return 0 when at least pixel shader 1.4 is available on that machine. *)
    function GetRenderCapability: s32; virtual; stdcall;
  end;

implementation

{ TMaterialRenderer }

function TMaterialRenderer.GetRenderCapability: s32;
begin
  Result := 0;
end;

function TMaterialRenderer.IsTransparent: Boolean;
begin
  Result := False;
end;

function TMaterialRenderer.OnRender(Service: TRendererServices;
  vtxtype: E_VERTEX_TYPE): Boolean;
begin
  Result := True;
end;

procedure TMaterialRenderer.OnSetMaterial(const Material,
  LastMaterial: SMaterial; ResetAllRenderstates: Boolean;
  Services: TRendererServices);
begin
end;

procedure TMaterialRenderer.OnUnsetMaterial;
begin
end;

end.
